Biopsies are performed on human patients as a means of investigating a suspicious tumor, mass, or growth, on or within the patient. The tumor is identified by visual examination, palpitation, x-ray, MRI, ultrasound imaging, or other detection means. Once identified, there is a pressing need to rapidly evaluate the tumor as to whether it is malignant, or life threatening, or benign. This evaluation is generally performed by taking a biopsy. In a biopsy, a sample of tissue is removed from the patient and examined, usually under a microscope. Biopsies can be performed as an open or percutaneous procedure. With today's focus on women's breast cancer and the high mortality rate associated with this disease, there has been a tremendous effort to develop improved percutaneous methods of acquiring breast biopsies for analysis. If a cancer is detected and treated in the early stages of growth, there is a significant increase in the survival rate of the patient.
Percutaneous biopsies are usually performed with a needle-like instrument as a fine needle aspiration (FNA) or a core biopsy. The fine needle aspiration instrument retrieves a small amount of cells or cluster of cells that can be examined as a smear. In a core biopsy, a core of tissue is removed from the patient. It is important to note that the core biopsy method is attaining favor among physicians as it provides an intact tissue sample of the suspected area which makes it easier to properly diagnose the type, condition, and location of the suspected tissue mass.
The original core biopsy devices consisted of a coring needle, e.g. a hollow tube with a sharpened edge to obtain a plug of tissue. Such a device was inserted into the tumorous mass and withdrawn, sometimes without a core sample. Once the coring device was removed from the body, the plug of tissue was pushed out of the coring needle.
Whereas the coring needles did provide a tissue core, they were slow and had the additional disadvantage of removing a section of healthy breast tissue from the skin to the suspected cancerous site. If repeated tissue samples were required, the coring needle caused repeated trauma to the breast tissue from the repeated insertion and withdrawal of the needle through the tissue.
In response to the above deficiencies, an improved method of taking multiple biopsy samples was developed. The TRUE CUT.RTM. needle (sold by Travenol Laboratories, Deerfield, Ill.) provides the following advantages over the original core biopsy device or the use of hollow needles. First, the TRUE CUT.RTM. device has a pointed stylus that enables the device to penetrate the body to the surgical site without removing a core of healthy tissue. Second, the device uses an exterior sliding cutter tube that covers or shields the biopsy or tissue sample within the device as it is being withdrawn. To obtain a tissue sample, the TRUE CUT.RTM. needle depends upon the passive prolapse of tissue into a tissue receiving notch within the stylus. Once the tissue is prolapsed into the notch, the cutting tube is advanced to sever the tissue sample.
The above device was revolutionary in the field at the time because it only removed tissue samples from the desired surgical site and removed the sample from the body in an intact manner. However, the device still required multiple insertions and removals from the surgical site, which did not address the repeated tissue trauma issues. Additionally, size and shape of the tissue samples tended to be inconsistent. This may have been caused by the need for the tissue to passively prolapse into the device and by the forced migration of the tissue away from the cutter as it is advanced.
In response to the need for a method to acquire consistent tissue samples, the addition of vacuum to a biopsy device was created. The vacuum was applied to the tissue receiving chamber to draw the tissue within the chamber. This type of device offered consistent tissue sample size and held the tissue in place as the knife was advanced to sever the tissue. U.S. Pat. No. 3,590,808 to Wulf Muller discloses such a device.
Whereas the Muller device did address the need for vacuum to effectively hold the tissue in place to provide consistent samples, it did require an insertion and a removal of the device from the body for each tissue sample.
Another type of device is disclosed in U.S. Pat. No. 5,106,364 to Mineki Hayafuji et al. The Hayafuji et al. device uses suction to the tissue for drawing the tissue into an aperture or multiple apertures within the biopsy device. The multiple aperture biopsy device described by Hayafuji et al. has multiple ports in a longitudinal orientation, e.g. the ports are linearly spaced along the longitudinal axis. Once the tissue is drawn or prolapsed into the aperture (or apertures), an internal cutting blade (or blades) is used to sever the tissue within the biopsy device. Once the tissue sample is sectioned, it is withdrawn from the instrument by the vacuum.
The Hayafuji et al. device was a breakthrough device in that: it did not need to be withdrawn and reinserted; provided multiple tissue samples in a short period of time; used vacuum to draw the tissue into the instrument for improved cutting; and withdrew the tissue samples out of the body. However, the Hayafuji at al. device was better suited for the removal of a tissue mass as it did not provide intact tissue samples for analysis. Additionally, the device produces multiple cut tissue samples which are not withdrawn from the body in an orderly manner, so the actual site location of the tissue sample is suspect at best.
Recognizing the shortcomings of the previous devices, an improved surgical biopsy device was developed and is disclosed in U.S. Pat. No. 5,526,822 to Burbank et al. The device is embodied in the MAMMOTOME.RTM. biopsy device (manufactured and sold by Ethicon Endo-Surgery, Inc., Cincinnati, Ohio). It is an automated surgical biopsy device that is inserted into a surgical site only once for removing multiple tissue samples through the use of vacuum to draw the tissue into the device. The vacuum is also used to hold the tissue while it is cut in order to provide elongated, intact tissue samples. This device includes an outer piercing needle with a single aperture port and an inner rotating tubular cutter that cuts tissue drawn into the single aperture port. The tissue is withdrawn from the surgical site within the tubular cutter and is ejected in a biopsy cage or cartridge for ease of identification. Additionally, the MAMMOTOME.RTM. device can be attached to a stereotactic table which provides visualization of the tissue site, via ultrasound or other visualization means, and provides precise movement of the device into the suspected surgical site.
It is important to note that, presently, the MAMMOTOME.RTM. device utilizes only one tissue port. Hence, multiple samples can be taken from the site in 360 degree fashion, by rotating the outer circumference of the piercing needle in order to position the aperture port at various locations around the circumference of the piercing needle.
Presently, there is no known a surgical biopsy device that can meet all of the needs outlined above, as well as provide a biopsy device that can provide tissue sampling through the use of a removable tissue extractor.